Purpose: We evaluated the feasibility of a using urine sensor for voiding cystourethrography (VCUG) and its implications for fluoroscopy time reduction. Materials and methods: Institutional Review Board approved the study protocol. Study population included children less than 5 years old referred to our institution for VCUG. Patients with known vesicoureteral reflux or any pacing device were excluded from the study. The urine sensor consists of an electrode that senses the fluid, an electrical circuit and an indicator to provide visual signal. The urine sensor electrode was placed on the medial thigh in the proximity of the catheter close to the urethral opening, but without direct contact to it. A standard VCUG examination was performed with retrograde filling of the urinary bladder. Once the bladder was full, fluoroscopy of the voiding stage was initiated when the indicator blinked. Peak kV and fluoroscopy time were recorded. Results: Seven patients underwent VCUG with urine sensor and 22 patients without urine sensor. The urine sensor provided a reliable indication of voiding onset. The fluoroscopy time was significantly shorter with urine sensor use (1.99 min) than without urine sensor use (4.33 min) (p = 0.001). In patients with normal VCUG, fluoroscopy time was also significantly shorter with urine sensor use (2.13 min) than without urine sensor use (4.39 min) (p < 0.001). Conclusion: VCUG studies with the help of the urine sensor are feasible and its use may result in significant reduction in fluoroscopy time.
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